diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 200793b5e..b38f81e99 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -626,6 +626,6 @@ class AuthHandler(BaseHandler):
             Whether self.hash(password) == stored_hash (bool).
         """
         if stored_hash:
-            return bcrypt.hashpw(password, stored_hash) == stored_hash
+            return bcrypt.hashpw(password, stored_hash.encode('utf-8')) == stored_hash
         else:
             return False